Air inlet arrangement for two-cycle internal combustion engines



July- 5, 1938. vSASS 2,123,065 AIR INLET ARRANGEMENT FOR TWO-CYCLE INTERNAL COMBUSTION ENGINES Filed June 8,- 1935 Figl.

L Inventor":

' Friedrich Sass His ttorneg.

Patented July 5, 1 938 PATENT OFFICE.

AIR INLET ARRANGEMENT FOR TWO-CYCLE INTERNAL COMBUSTION ENGINES Friedrich. Sass, Berlin-Charlottenburg, Germany,

assignorto General Electric Company, a corporation of New York Application June 8, 1935, Serial No. 25,604 a In Germany June 23, 1934 2 Claims.

The present invention relates to air inlet arrangements for two-cycle internal combustion engines. In solid injection engines of this kind the scavenging air must be conducted through the combustion space with a circling or rotary motion of a definite velocity in order to obtain thorough scavenging and good combustion. Experience has shown that in cases where the air circles too slowly the combustion becomes worse and in cases wherethe air circles too fast the fuel consumptionincreases: In two-cycle combustion engines with" air inlet ports in the cylinder liner the desired air rotary motion may be obtained in many cases by properly forming the air inlet or scavengingports or channels. However, it may easily happen that for some reason the most favorable air rotary motion is not obtained, and in addition it is desirable to improve old or finished machines in order to effect better scavenging of the cylinders.

The object of my invention is to provide an improved construction of air inlet arrangements for two-cycle combustion engines whereby the most favorable air rotary motion with a consequent thorough scavenging and effective combustion in the cylinder is obtained. This is accomplished in accordance with my invention by the provision of a plurality of guide vanes in the path of the air to the air inlet ports in the cylinder wall or walls. These guide vanes effect a circling or rotary motion of the air, which motion is maintained within the cylinder or cylinders.

For a better understanding of what I consider to be novel and my invention, attention is directed to the following specification and the claims appended thereto in connection with the accompanying drawing.

In the drawing, Fig. 1 illustrates somewhat diagrammatically a combustion engine cylinder in accordance with my invention; Fig. 2 is a sectional view along the line 2-2 of Fig. 1, and Fig. 3 shows a similar sectional view embodying a modification according to my invention.

The arrangement as shown in Figs. 1 and 2 comprises a cylinder wall In, a head I I fastened to the wall It, and a piston I2 slidably arranged within the wall It. The cylinder wall I is surrounded by a jacket l3 which forms an annular space M for cooling the cylinder. Cooling medium such as water is conducted to the cooling space 14 through an inlet l5 and discharged therefrom through an outlet 16. The wall Ill and the jacket I3 are provided with inlet ports I! for conducting air into the interior of the cylinder, and outlet ports l8 for discharging the combustion gases. The inlet ports l1 receive air' from a container or manifold 19 and the outlet ports 18 discharge combustion gases into a discharge manifold 20. The ports I1, [8' in the walls II] of the cylinder are directed in the present instance upward and their central lines form tangents 2la. to a small circle 2| around the axis of the cylinder. The arrangement in this respect is similar to the one disclosed in the U. S. Patent 1,833,861 issued on November 24, 1931 and assigned to the same assignee as the present application. The directing and forming of the ports are not absolutely necessary because the effect may be obtained with my invention more specifically with the provision of guide vanes as will be described presently. It is also important to note that it is sufiicient to provide inlet ports extending over a portion only of the circumference of the cylinder wall. In the present instance I have shown three inlet ports 11 and three outlet ports I8, in diametrically opposite portions of the cylinder Wall, with each of the two sets of ports extending over about 180 angular degrees of the cylinder wall.

In the passage between the air container l9 and the scavenging inlet ports IT, I provide in accordance with my invention a plurality of guide vanes 22 for guiding the air, more specifically for imparting to the air a circling or rotary motion, which motion is maintained within the cylinder.

In the present arrangement, as indicated in Fig.

2, four guide vanes are provided of which the two outer guide vanes are somewhat longer than the inner guide vanes. They are directed to guide air into the cylinder through the ports I! in such direction as to obtain a minimum of interference from the dividing wall between the ports. The length and the shape of the different guide vanes may be calculated or determined by experiments so as to obtain the best result, to wit: through cleaning of the cylinder and good combustion, or, from another viewpoint, minimum consumption of fuel. The guide vanes 22 in the present instance are produced by a simple manufacturing process. They are cut out from a steel sheet 23 suitably secured between the cylinder jacket I 3 and the air manifold I9. The direction of air flow through the vanes into the cylinder is indicated in Figs. 1 and 2 by arrows 24.

The arrangement of Fig. 3 comprises a cylinder having a wall 25 with air inlet ports 26 and outlet ports 21 corresponding to the ports I! and I8 respectively, of Fig. 1. The cylinder wall is surrounded by a water jacket 28 corresponding to the jacket l3 of Fig. 1. An air manifold 29 corresponding to the manifold IQ of Fig. 1 is secured to the water jacket 28 and communicates with the ports 26. A plurality of guide vanes 30 corresponding to the vanes 22 of Figs. 1 and 2 are disposed in the passage of the air between the manifold 29 and the air inlet ports 26. In accordance with the modification of my invention, the guide vanes 30 are secured to a steel sheet 3| by hinges 32 and in addition are pivotally connected to a rod 33 secured to a lever 34 permitting adjustment of the guide vanes. It is to be noted that in the present instance some of the guide vanes are straight and others curved to obtain the best result.

With my invention I have provided an improved arrangement for conducting the air into the cylinders of two-cycle internal combustion engines whereby a considerable saving in fuel and a clear exhaust are obtained.

A special advantage of my invention is that it can be provided in finished machines. Furthermore, with the application of my arrangement it is no longer necessary to provide the air inlet ports along the entire circumference of the cylinders, but it is suflicient if these air inlet ports are provided in known manner along a part only of the circumference of the cylinder walls. As pointed out above the guide vanes are also effective in machines, the ports of which are radially directed, that is without consideration as to the desired air rotary motion within the cylinders. Also, in these cases a considerable improvement of the operation of two-cycle combustion engines may be obtained by the provision of additional guide vanes in accordance with my invention. The adjustment of the guide vanes may be effected simply by observing the appearance of the exhaust gases, that is the vanes are adjusted until the gases exhausted from the engines are clear or invisible. The guide vanes may also be simply adjusted in accordance with the fuel consumption.

What I claim as new and desire to secure by Letters Patent of the United States, is:

1. In a two cycle internal combustion engine having a cylinder with a plurality of circumferentially spaced air inlet ports, the combination of an air container provided with an opening registering with said ports and provided with a plurality of adjustable guide vanes arranged in said opening and in proximity to said ports for effecting a rotary motion of the air moving from said container to said cylinder, said rotary motion being adjustable during operation of said engine by means of said adjustable vanes whereby the most efiicient fuel consumption may be obtained for difierent operating conditions.

2. In a two cycle internal combustion engine, the combination of a cylinder casting provided with a plurality of circumferentially spaced air inlet ports in its side wall which normally direct air substantially toward the center of said cylinder, a sheet metal air tank attached to said cylinder, and provided with openings substantially registering with said ports, and vanes projecting from said openings towards said ports and shaped so as to direct air from said tank through said ports in a direction which is at an angle to the normal air flow through said ports to effect a rotary motion of said air in said cylinder.

FRIEDRICH SASS. 

